Means for discharging the exhaust from heaters



Nov. 24, 1964 F. NIKODEM 3,158,114

MEANS FOR DISCHARGING THE EXHAUST FROM HEATERS Filed June 20, 1963 ,Hiorney United States Patent 3,158,114 MEANS FOR DHSCHARGING THE EXHAUST FRGM HEATERS Franz Nilrodem, Stoclrtiorf, near Munich, Germany, assignor to Wehaste Wen: G.m.'u.lil., Stockdorf, near Munich, Germany Filed June 24 1963, Ser. No. 289,318 Claims priority, application Switzeriand, July 6, 1962, 8,079/62 6 (Ilaims. (Cl. 110-162) This invention relates to means for discharging the exhaust gases of air heaters of the kind equipped with a blower for the combustion air, which draws air for combustion through a suction passage into the combustion chamber of the heater, and delivers the exhaust gases thence to an outlet passage.

In appliances of the above mentioned type atmospheric influences, such as inblown wind or negative pressure due to ambient air currents, sometimes cause trouble, and to meet this difliculty it has been proposed to locate the inlet of the suction passage near to the outlet opening of the exhaust passage, since in this case the disturbances occurring through air currents at the opening of these passages tend to cancel one another. This arrangement however cannot be used in all cases. In many cases the pipe for the combustion air and the exhaust pipe must open into the atmosphere at points far distant from one another. Different pressure conditions at the two openings may then make it impossible to operate the burner reliably with an optimum ratio in the air-fuel mixture. The continuous fluctuation of conditions also make it efiectively impossible to correct operations by adjustment of the blower for the combustion The use of additional exhaust blowers, with or without injectors, is also subject to the same fluctuations. Furthermore, in some cases difiiculty arises from the influence of different flow resistance in long exhaust gas pipes on the combustion efiiciency, and the problem of the formation of condensate in long exhaust gas pipes may also arise.

The present invention aims at providing means which permit reliable operation of heaters under favourable, uniform conditions of combustion, despite varying wind conditions, and even during squalls.

The aim is achieved by connecting both the exhaust passage and the suction passage for the combustion air in communication with a common protecting space which has an inlet and an outlet, and is provided with a blower, disposed in the flow path formed by the inlet, the protective space, and the outlet, adapted to cause a flow of air through the protective space.

The main air current thus produced has several times the energy of the current of combustion air which is drawn off from the main air current, and after burning in the combustion chamber is returned as exhaust to the main air current. This mixed gas drawn in and passed on by the blower in the protective space is given an outlet energy corresponding to the external disturbances to be expected.

If inblowing or obstruction should now occur at the outlet of the protective space, in apparatus according to the invention, the only result is that less air is delivered through the protective space, that is to say the small negative pressure existing if the blower is a suction blower located in the outlet passage will decrease.

The delivery of the blower for the combustion air and hence the conditions of combustion of the heater, are however not effected thereby. The ratio of the mixture of air and exhaust gases, delivered by the blower of the protective space into the atmosphere, will merely vary.

As already indicated above, the blower of the protective space is most conveniently situated in the outlet pasice sage. The air can thus be more smoothly and simply guided through the protective space.

Any turbulence which may occur in the protective space may be reduced by means of a flow protection plate. In addition, the blower of the protective space should be so dimensioned that with a heavy back-pressure of wind on the outlet aperture it will still have at least twice the rate of delivery of the air as that provided by the combustion blower of the heater, in order that it may be decisive in determining the direction of flow in the protective box.

It is also of importance that the mouth of the suction passage for the combustion air, viewed in the direction of flow of the air flowing from the inlet to the outlet of the protective box, shall be situated in advance of the mouth of the exhaust passage, in order that exhaust gases will not enter the suction passage for the combustion air.

If for the purpose of eliminating vibration there are provided means of any type for interruption of draught in the exhaust gas pipe of the heater, according to another feature of the invention the draught interruption may be vented through a pipe the end of which remote from the draught interruption connection, leads into the protective space.

It is also convenient to provide the protective space box at its lowest point with an outlet through which any water or other liquid can be drained off.

One example of a heater according to the invention will now be described with reference to the accompanying drawing, with the aid of which still further features of the invention will be illustrated.

As shown in the aforesaid drawing a heater 1 has a blower 2 for the combustion air and a fuel pump 3 which, together with the rotary atomiser 4 and a heating air blower (concealed by the outer walls), is driven by an electric motor 5. During the operation of the heater 1 the air for combustion blower 2 sucks air through the suction passage 6, delivers it to the combustion chamber 7 and thence through an annular cylindrical heat transfer passage 8 to the exhaust gas passage 9 in which a draught interrupter or shield 10 is provided, which is vented by a vent pipe 11. The suction passage 6, the exhaust gas passage 9, and the vent pipe 11 all lead into a protective chamber 12 through which, by means of a suction blower 13, air is caused to flow from an inlet 14, in the form of a pipe to the outlet 15, which is in the form of a pipe.

From the main air current forming inside the protective space 12, air for the combustion blower 2 of the heater 1 is drawn off through the pipe 6 and returned as exhaust through pipe 9 into the main air current.

An outlet 16 enables water which may have entered,

or any condensate which may accumulate, to be drained off from the protective space 12.

Partitions 17 and 18 projecting above the ends of the passages 6, 9, and 11 in the protective space are advantageous, and are preferably disposed inside a ring plate 19 surrounding the passages, so that annular passages 20, 21 and 22, each open at top and bottom, are formed respectively around the ends of the passages 6, 9 and 11. Turbulence can thus be very simply reduced. The main air current inside the protective space 12 is preferably passed above the devices 17, 18, 11 serving as flow protection, by suitable location of the inlet passage 14 and outlet passage 15.

Caps or covers 23 and 24 over the inlet passage 14 and outlet passage 15 are preferably provided.

The volume of the protective space, less that of the inlet and outlet passages, should not be smaller than that of the combustion chamber of the heater.

arcane If a plurality of heaters are provided, a common protective space may be used for all of them.

The invention is not restricted to the exemplary embodiment illustrated, but may be subjected to modifications and additions,'without departing from the scope of the invention, as defined in the appended claims.

What I claim is:

1. The combination with a heater having a combustion chamber, an inlet passage and an outlet passage each having one of their ends communicating with said combustion chambenand a heater blower for delivering air to said combustion chamber through said inlet passage for causing the products of combustion to be exhausted from said combustionchamber through said outlet passage, of a protective chamber having a combustion air inlet and a spaced exhaust gas outlet, first conduit means providing communication between the inlet passage for said combustion chamber and the interior of said protective chamber, second conduit means providing commu nication between the outlet passage for said combustion chamber and the interior of said protective chamber, and blower means communicating with said protective chamber for maintaining a flow of air through said protective chamber.

2. The combination defined in claim 1 wherein said blower means is disposed in said exhaust gas outlet.

3. The combination defined in claim 1 wherein said blower means has a delivery rate of at least twice the delivery rate of said heater blower.

4. The combination defined in claim 1 wherein said first conduit means providing communication between the inlet passage for said combustion chamber and said protective chamber is disposed in advance of said second conduit means providing communication between the outlet passage for said combustion chamber and said protective chamber.

5. The combination defined in claim 1 wherein said second conduit means includes an exhaust gas injector disposed within the portion of said conduit adjacent said combustion chamber, and ancillary conduit means for venting said injector, said ancillary, conduit means providing communication between said injector and said protective chamber. j

6. The combination defined in claim 1 wherein said protective chamber includes a liquid drainage outlet means. 7

References Qited by the Examiner UNITED STATES PATENTS 2,087,983 7/37 Martin n 126-85 2,517,398 8/50 McCollum 12685 JAMES w. was'rnAvnn, Primary Examiner. 

1. THE COMBINATION WITH A HEATER HAVING A COMBUSTION CHAMBER, AN INLET PASSAGE AND AN OUTLET PASSAGE EACH HAVING ONE OF THEIR ENDS COMMUNICATING WITH SAID COMBUSTION CHAMBER, AND A HEATER BLOWER FOR DELIVERING AIR TO SAID COMBUSTION CHAMBER THROUGH SAID INLET PASSAGE FOR CAUSING THE PRODUCTS OF COMBUSTION TO BE EXHAUSTED FROM SAID COMBUSTION CHAMBER THROUGH SAID OUTLET PASSAGE, OF A PROTECTIVE CHAMBER HAVING A COMBUSTION AIR INLET AND A SPACED EXHAUST GAS OUTLET, FIRST CONDUIT MEANS PROVIDING COMMUNICATION BETWEEN THE INLET PASSAGE FOR SAID COMBUSTION CHAMBER AND THE INTERIOR OF SAID PROTECTIVE CHAMBER, SECOND CONDUIT MEANS PROVIDING COMMUNICATION BETWEEN THE OUTLET PASSAGE FOR SAID COMBUSTION CHAMBER AND THE INTERIOR OF SAID PROTECTIVE CHAMBER, AND BLOWER MEANS COMMUNICATING WITH SAID PROTECTIVE CHAMBER FOR MAINTAINING A FLOW OF AIR THROUGH SAID PROTECTIVE CHAMBER. 